Phosphatidylcholine applications

I. Vikholm, W.M. Albers, H. Valimaki, and H. Helle, In situ quartz crystal microbalance monitoring of Fab-fragment binding to hnker lipids in a phosphatidylcholine monolayer matrix application to immunosensors. Thin Solid Films 327, 643-646 (1998). 

Petkovic, M., Muller, J., Muller, M., Schiller, J., Arnold, K., Arnold, J. Application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for monitoring the digestion of phosphatidylcholine by pancreatic phospholipase A2. Anal. Biochem. 2002, 308, 61-70. 

The peculiar electrochemical behaviour of electrode surfaces coated with a layer of phosphatidylcholine (PC) adds a new dimension to the practical applications of this type of sensor as it enables development of electrochemical processes within a lipid layer. Redox-active amphiphiles readily... 

The application of high-sensitivity ICP-MS detectors coupled to HPLC has enabled the detection of trace arsenic compounds present in marine animals. Thus, arsenocholine has been reported as a trace constituent (<0.1% of the total arsenic) in fish, molluscs, and crustaceans (37) and was found to be present in appreciable quantities (up to 15%) in some tissues of a marine turtle (110). Earlier reports (46,47) of appreciable concentrations of arsenocholine in some marine animals appear to have been in error (32). Phosphatidylarsenocholine 45 was identified as a trace constituent of lobster digestive gland following hydrolysis of the lipids and detection of GPAC in the hydrolysate by HPLC/ICP-MS analysis (70). It might result from the substitution of choline with arsenocholine in enzyme systems for the biogenesis of phosphatidylcholine (111). 

In contrast to the conventional emulsions or macroemulsions described earlier are the disperse systems currently termeraiicroemulsions. The term was Lrst introduced by Schulman in 1959 to describe a visually transparent or translucent thermodynamically stable system, with much smaller droplet diameter (6-80 nm) than conventional emulsions. In addition to the aqueous phase, oily phase, and surfactant, they have a high proportion of a cosurfactant, such as an alkanol of 4-8 carbons or a nonionic surfactant. Whereas microemulsions have found applications in oral use (as described in the next chapter), parenteral use of microemulsions has been less common owing to toxicity concerns (e.g., hemolysis) arising from the high surfactant and cosolvent levels. In one example, microemulsions composed of PEG/ethanol/water/medium-chain triglycerides/Solutol HS15/soy phosphatidylcholine have been safely infused into rats at up to 0.5 mL/kg. On dilution into water, the microemulsion forms a o/w emulsion of 60-190 nm droplet size (Man Corswant et al., 1998). 

Application to Complex Lipids. Structural information may be obtained for complex lipids as a result of remote charge site fragmentation (23). The negative ion FAB spectra, as well as the colllslonal activation spectra of the major ions, have been obtained for a number of phospholipids, including phosphatidylcholines, phosphatidylserlnes, phosphatidylInositols, cardlollpid,... 

Figure 3 Gel-state versus liquid-state application of vesicles prepared from dilauryl-phosphatidylcholine and septaoxyethylene alkylethers or distearylphosphatidylcholine and cholesterol hemisuccinate. A cross-section of rat skin visualized with confocal laser scanning microscopy after 6 h application. The dye used was fluorescein-phosphatidyl ethanol amine. The vesicles were applied onto rat skin in vivo.

Effects of the Topical Application of Fluid-State Phosphatidylcholine. 303... 

EFFECTS OF THE TOPICAL APPLICATION OF FLUID-STATE PHOSPHATIDYLCHOLINE... 

Prior to spotting of samples, the plate is scored lengthwise at 0.5- to 1.0-cm widths by use of a stainless steel needle. Excess silica gel is removed by gentle tapping of the plate, and the samples are ready for application. The outer lanes of the scored plate are reserved for standards (e.g., phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, lysolecithin, and others as desired), which are readily available from several biochemical companies. Aliquots of the unknown lipid sample, which contain sufficient P, as detected by the qualitative spray above, are spotted on two to three lanes (usually in a volume ratio of 1 2 3) approximately 1.0 cm above the bottom of the plate. This is called the origin. 

The ionic characteristics of phosphatidylethanolamine and phosphatidylserine provided a basis for their separation from the neutral phospholipids, such as phosphatidylcholine and sphingomyelin. This involved application in chloroform-methanol (1 1, v/v) of a cellular lipid extract to a... 

Non-Forster fluorescence quenching of trans-etiochlorin by magnesium oc-taethylporphine in phosphatidylcholine vesicles gives evidence for a statistical pair energy trap. Energy transfer also occurs in the excited singlet manifold of chlorophyll. " The photophysics of bis(chlorophyll)-cyclophanes, models of photosynthetic reaction centres, have been explored for use in artificial photosynthesis.Picosecond time-resolved energy transfer in phycobilosomes have also been studied with a tunable laser. The effect of pH on photoreaction cycles of bacteriorhodopsin, " the fluorescence polarization spectra of cells, chromatophores, and chromatophore fractions of Rhodospirillum rubrum, and a brief review of the mechanism and application of artifical photosynthesis are all relevant to the subject of this Chapter. 

A lipid system of biosomes composed of phosphatidylcholine from soybean and medium-chain monoacylglycerol and low-molecular-weight heparin (LMWH), used in the treatment and prevention of thromboses, was reported (51). Heparin is known as having poor oral absorption. The system is applicable for oral and parentral administration as well as for enhancing dermal, rectal, and nasal absorption of other dmgs. 

The first synthetic route which may serve as a potential source of phosphatidylcholine-bearing docosahexaenoic acid (85) and tetracosahexanoenoic acid for physiological studies has been described. This method may also be applicable to the synthesis of phosphatidylocholine homologues having longer chains, such as those identified in bovine retina. ... 

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